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Topic: Stair climbing robot (Read 7550 times)

Does anybody have any plans or designs for a stair climbing robot that i could modify? it doesnt have to be a bi-ped and id rather if it wasnt, as long as the design could reliably climb and descend stairs.

I haven't actually built one myself, but a quick Google search turned up some interesting sites...

You can go with a "tread" approach (think military tank) where the treads are longer than the distance between two outside corners of the steps.You can go with a "whegs" approach (google on "whegs" to get different designs)You can go with an articulated frame approach using six wheels

I am desinging(google sketchup) a robot with 4 legs controlled by servo's that can climb stairs and other various obstacles. If you want I can upload it later.. be warned though its only half complete and a lot of things would still change on it..

As far as controlling the legs, I am borrowing designs that use gears to do it. Essentially you place gears at the edge of each leg segment and have them set a set distance apart. Then link the metal legs with some kind of metal bar that can rotate. Because the gears simply move around eachother, the segments never move farther or closer to eachother.

It does need to be autonomous, and capable of overcoming everyday obstacles - stairs being my main problem at the mo. I want to try to steer clear of cat tracks.

The "whegs" approach would work if you optimised the leg length for stairs, but unfortunateley not all stairs have standard riser sizes, and i have a feeling that making "whegs" which can grow/ shrink wouldnt be that easy.

Quadrapeds also wouldn't be too easy either since dogs have problems on stairs.

Im considering something like a caterpillar design which can lift the front section onto a step and them manipulate its body to pull the rear end up.

the robot would have 3 wheels (each wheel being a tri-star) the 2 at the back would be driven as a differential drive, but not in the normal one motor per wheel arrangement. instead I intend to use an adder-subtracter gearing system

The front wheel would also be a tri-star, but the drive to the wheels and the drive to the tri-star would be separate, and able to brake independently. The tri-star would have to be able to lock so that it runs free on one wheel of the three, while on flat ground. This is so that the wheel (in fact whole tri-star system) can spin like a caster would. Finally the two back wheels, and the front wheel would have to be connected via a Y shape (where the bottom of the Y is the front wheel and the two points at the top are the back wheels) which can pivot at the center. This would allow the front and back wheels to be brought closer together and further apart for different stairs, and to be able to raise and lower the height of the robot. The main body of the robot would then be attached to a forth and final beam attached Perpendicular to the center of the Y (coming up off the screen). This alows the robot to lean forward and back to ajust balance. This will help allot when coming down steps, as well as being able to push the front wheel out in front.

It sounds complicated, because it is, and I have put much thought in to this. You would have to calculate the size of the robot, based on wheel sizes to deal with stairs.